The Gowin DCS (Dynamic Clock Selector) primitive is used to dynamically switch between four clock inputs, GCLK0-GCLK3, via a CRU (Clock Router Unit). It has two clock switching modes: "Non-glitchless" and "Glitchless". In Non-glitchless mode, the output clock can glitch depending on the time of switching. In Glitchless mode, it is possible to avoid glitches by configuring the CLKSEL signal to switch the clock signal using DCS_MODE.

This device is supported in Apicula.

DCS #(
    .DCS_MODE(DCS_MODE)
) dcs_inst (
    .CLK0(CLK0),
    .CLK1(CLK1),
    .CLK2(CLK2),
    .CLK3(CLK3),
    .CLKOUT(CLKOUT),
    .CLKSEL(CLKSEL),
    .SELFORCE(SELFORCE)
);